HSTCAL Release Notes

The HSTCAL package provides an environment for compiling IRAF tasks written in
C without using IRAF at all. The HSTIO image and tables C API has been
replicated using CFITSIO. This API was used to compile the ACS calibration code
CALACS, WFC3 calibration code CALWF3 and STIS calibration code CALSTIS.

CALWF3

Version 3.1.6 of CALWF3 was installed in Nov 2013 and remains the calibration software
that gets used in the archive for pipeline calibrations. It replaced the now
outdated STSDAS/IRAF based version (both of which have been removed from
STSDAS). This release includes calwf3 related tasks; namely, wf32d, wf3ccd,
wf3ir, and wf3rej.

No changes since the last release of HSTCAL with CALWF3.

CALACS

Version 8.2.0 of CALACS has been included in this release. Changes from previous
release include:

Fixed HSTIO read/write bug in ACSREJ so file is closed properly before being
reopened in a different IO mode

Separated PCTECORR from ACSCCD and made it into its own ACSCTE step

CALSTIS

This release includes, for the first time, the calibration code for STIS:
CALSTIS. This version continues the development of CALSTIS that was previously
released under STSDAS.

Version 3.4 (13-November-2013) includes the following changes made since the
last public release:

In the code for echelle scattered light correction, an image of the PSF of
the telescope is read from a reference file. This image covers 0.2 by 0.2
arcseconds and is oversampled. For echelle data, the aperture is usually no
larger than this, so the PSF image will be truncated to match the aperture used
for an exposure. The code to truncate the PSF did not take into account the
case of an aperture that was larger than 0.2 arcsec, however. This has been
fixed.

Use the mean instead of median when applying the NUV-MAMA dark reference
image.

A bug was fixed in the background subtraction for the X1D extraction step.
Due to roundoff errors, the number of pixels used for the background region was
sometimes smaller than intended.

For NUV data taken since SM4, the latest calibration developed by C. Cox now
gets used to scale the dark reference image. Calstis now opens the TDCTAB and
determines which format it is from the columns that are found in the table. The
temperature and time correction factor then gets determined by evaluating either
Colin's newly calibrated expression or the pre-SM4 expression.

When the image I/O interface used by the C versions of the pipeline software
was first written, there was code in calstis that opened a file readonly, then
opened it again read/write without first closing the file (this was fixed some
time ago). The IRAF interface permitted that, but CFITSIO -- which is used in
the current (hstcal) version of calstis -- does not. As a workaround, when the
openInputImage function in the hstcal version of the image I/O interface was
first written a few years ago, it opened the input file read/write. This was
highly undesireable, however, because calstis would fail if the user did not
have write permission for the input file, so the openInputImage function has now
been modified to open the input file readonly. This bug also affected CALACS
and CALWF3 where it was corrected as well (noted as "fixing an HSTIO read/write
bug").

IMPHTTAB

This package provides all the support necessary for interpreting IMPHTTAB
reference files. Use of the IMPHTTAB reference files replaces direct calls to
IRAF's synphot package when computing the photometry keywords. The following
bugs and enhancements have been implemented since the last release:

Fixed a bug in PHOTCORR that crashed when PHOT* value is zero, which is a
valid value for SBC blocking filter.

Added support for MJD extrapolation. This is actually for STIS Team but would
affect other instruments (such as ACS) should they require this feature at some
later time.

The code was updated to allow acceptence of IMPHTTAB reference files with
varying extension numbers. Previously, all HST instrument files had the same
number of extensions and they were explicitly read in, but since WFC3 has added
extensions for use with the new photometry scaling routine a code update was
needed. This update is backwards compatable.